The goal of the proposed research is to identify and predict the role of voluntary sterilization in fertility decline in developing countries. The factors that influence governments to provide sterilization upon request and the antecedents and consequences of undergoing the procedure will be explored. Substantively, the proposal will analyze the prevalence, correlates, probability, and demographic impact of voluntary sterilization and to relate the analysis to the population and family planning program policies of various countries. Findings from the Westinghouse Contraceptive Prevalence Surveys will serve as the empirical data base. The prevalence of contraceptive sterilization across countries and among various ethnic, religious, and educational groups within countries will be analyzed through the calculation of simple estimates. Differentials in prevalence, utilizing various definitions of potential clients for sterilization procedures, will be analyzed by various life-cycle and socio-economic variables, using bivariate and multivariate techniques. Estimates of annual births averted by sterilization will be made, and the demographic impact of sterilization will be assessed within the context of the mix of methods available and utilized within the countries. The research is expected to contribute to our understanding of the demographic effectiveness of sterilization, of the conditions under which it receives government support and promotion, and of the factors conducive to its adoption by individual couples.